Olefin isomers as lubricants, rate of penetration enhancers, and spotting fluid additives for water-based drilling fluids

ABSTRACT

The present invention provides non-toxic, biodegradable olefin isomers which may be used as lubricants, rate of penetration enhancers, and/or spotting fluids for water-based drilling muds. When used as a spotting fluid additive, the olefin isomers preferably are supplemented with functional additives, namely emulsifiers, viscosifiers, surfactants, and/or brine. When used as lubricants and/or rate of penetration enhancers, the olefin isomers preferably are used alone or in combination with surfactants.

FIELD OF THE INVENTION

The present invention relates to olefin isomers which may be added towater-based drilling muds which act as: (a) downhole lubricants; (b)rate of penetration (ROP) enhancers; and/or, (c) spotting fluids. Theadditives perform the following functions, respectively: (a) prevent adrill bit from sticking in a formation; (b) enhance the penetration of adrill bit through a formation; or, (c) free a drill bit when it becomeslodged in a formation during drilling.

BACKGROUND OF THE INVENTION

During the drilling of oil and/or gas wells, a drill bit at the end of arotating drill string, or at the end of a drill motor, is used topenetrate through geologic formations. During this operation, drillingmud is circulated through the drill string, out of the bit, and returnedto the surface via the annular space between the drill pipe and theformation. Drilling mud serves numerous functions, including: coolingand lubricating the drill string and drill bit; counterbalancing thepressures encountered in the formation using hydrostatic pressure;providing a washing action to remove the formation cuttings from thewellbore; and, forming a friction reducing wall cake between the drillstring and the wellbore.

During drilling, the drill string may develop unacceptable rotationaltorque or, in the worst case, become stuck. When this happens, the drillstring cannot be raised, lowered, or rotated. Common factors leading tothis situation include: (1) cuttings or slough buildup in the borehole;(2) an undergauge borehole; (3) irregular borehole development embeddinga section of the drill pipe into the drilling mud wall cake; and, (4)unexpected differential formation pressure.

Differential pressure sticking occurs when the drill pipe becomesimbedded in the wall mud cake opposite a permeable zone. The differencebetween (a) the hydrostatic pressure in the drill pipe, and (b) theformation pressure holds the pipe in place, resulting in sticking pipe.

Differential sticking may be prevented, and a stuck drill bit may befreed, using an oil/mud or an oil or water based surfactant composition.Such a composition reduces friction, permeates drilling mud wall cake,destroys binding wall cake, and reduces differential pressure.Unfortunately, many of such compositions are toxic to marine life.

Synthetic polyalphaolefins are non-toxic and effective in marineenvironments when used as lubricants, ROP enhancers, and/or spottingfluid additives for water-based drilling muds. A continuing need existsfor other non-toxic additives for water-based drilling muds which serveas lubricants, ROP enhancers, and/or spotting fluids.

SUMMARY OF THE INVENTION

The present invention provides non-toxic, biodegradable olefin isomerswhich may be used as lubricants, rate of penetration enhancers, and/orspotting fluids for water-based drilling muds. When used as a spottingfluid additive, the olefin isomers preferably are supplemented withfunctional additives, namely emulsifiers, viscosifiers, surfactants,and/or brine. When used as lubricants and/or rate of penetrationenhancers, the olefin isomers preferably are used alone or incombination with surfactants.

DETAILED DESCRIPTION OF THE INVENTION

When introduced at a certain volume downhole, the additives of thepresent invention act as lubricating agents and/or rate of penetrationenhancers, preventing drag and torque on an operating drill pipe. Whenintroduced at a greater volume downhole, the additives act as spottingfluids, which dislodge stuck drill pipe from the well bore.

As used herein, the term "olefin isomers" shall be defined as compoundshaving the following general formula:

    C.sub.n H.sub.2[(n-x)+1]

wherein n is between about 8-30; x is the number of carbon-carbon doublebonds in the isomer; and, x is between about 1-n/2. In a preferredembodiment, the double bonds in the olefin isomers are locatedinternally within the carbon backbone. As used herein, the phrase"internally within the carbon backbone" shall refer to a location otherthan at a terminal end of the carbon backbone.

The following general formula is believed to represent preferred olefinisomers of the present invention: ##STR1## wherein R¹ and R⁴independently are selected from the group consisting of straight chainalkyl groups with between about 1-28 carbon atoms, and branched alkylgroups with between about 1-28 carbon atoms, said branched alkyl groupsfurther comprising between about 0-2 substituents selected from thegroup consisting of alkyl groups with between about 1-5 carbon atoms;and, R² and R³ independently are selected from the group consisting ofhydrogen and alkyl groups with between about 1-5 carbon atoms, providedthat the total number of carbon atoms in said olefin isomers is betweenabout 8-30.

In a preferred embodiment, the olefin isomers comprise a mixture ofmolecules having primarily 16 and 18 carbon atoms, along with a smallerquantity of molecules having 14 carbon atoms. Preferred olefin isomershave a minor amount of unsaturation located internally within the carbonbackbone, and have between 0-2 substituents selected from the groupconsisting of alkyl groups having between about 1-2 carbon atoms.Preferred olefin isomers meet the applicable EPA toxicity requirementsfor discharge into U.S. waters.

Whether used as a lubricant, an ROP enhancer, or a spotting fluid, theolefin isomers may be supplemented with functional additives, such asemulsifiers, viscosifiers, surfactants, and/or brine. A spotting fluidblend preferably includes each of these functional additives. Alubricant or ROP enhancer preferably contains no functional additives,but may include surfactants. A combination of olefin isomers and anyfunctional additives hereinafter will be called an "olefin isomerblend."

The olefin isomers of the present invention may be formed bypolymerizing ethylene-which generally is derived from the catalyticcracking of naptha-using known procedures. Suitable procedures that maybe adapted by persons of skill in the art to form the olefin isomers ofthe present invention are described in UK Patent Application GB 2 166782A, incorporated herein by reference; and, Kirk-Othmer Encyclopedia ofChemical Technology (3d Ed. 1981), pp. 487-491, incorporated herein byreference. See also U.S. Pat. Nos. 3,482,000; 3,391,291; 3,689,584;3,663,647; 3,676,523; and, Hydrocarbon Process, 58(11) 128 (1979),referred to in the cited Kirk-Othmer text, and incorporated herein byreference.

Olefin isomers containing between about 8-30 carbon atoms generallyshould function in the present invention; however, isomers having fewerthan 14 carbon atoms are more toxic, and isomers having more than 18carbon atoms are more viscous. Therefore, olefin isomers having between14-18 carbon atoms are preferred, and isomer blends comprising primarily16- and 18-carbon atoms, with a small amount of dimers thereof andolefin isomers containing 14-carbon atoms, are most preferred.

Preferred commercially available olefin isomers for use in the presentinvention are C16/C18 Isomerized Olefins, which may be obtained fromChevron Chemical Co. The Chevron C16/C18 Isomerized Olefins generallyhave the following properties:

    ______________________________________                                        Carbon Number analysis                                                        C16 Olefins                     47%                                           C18 Olefins                     47%                                           C16 or C18 Dimers               5%                                            C14 and C20 Olefins             .sup.˜1%                                Density at 60° F.        0.70                                          Viscosity        @      40° C.                                                                         3.43 cSt                                                       @     100° C.                                                                         1.40 cSt                                      Absorbance/mm @ 1378 cm-1       10.4                                          Color                           Clear and Bright                              Cloud Point                     <15° F.                                ______________________________________                                    

Another suitable commercially available olefin isomer is C1618IO,available from Albemarle Corporation. C1618IO has the followingproperties:

    ______________________________________                                        Carbon #, wt %                                                                C14                   0.7                                                     C16                   54.3                                                    C18                   36.5                                                    C20                   8.2                                                     C22                   0.3                                                     Olefin Isomers, mole % (NMR)                                                  Linear terminal       1.7                                                     Linear internal       70.2                                                    Branched terminal     18.8                                                    Trisubstituted        9.2                                                     ______________________________________                                    

A preferred additive for use as a lubricant and/or rate of penetrationenhancer (lubricant/ROP enhancer) comprises 100% C16/C18 olefin isomers,such as C16/C18 Isomerized Olefins, available from Chevron Chemical Co.Preferred lubricant/ROP enhancers also comprise olefin isomer blendscontaining between about 90-100% by volume of primarily C16/C18 olefinisomers and between about 1-10% by volume surfactants. A preferredlubricant and/or rate of penetration enhancer, which currently comprises100% C16/C18 olefin isomers, is DFE 619, available from Baker HughesINTEQ. The lubricant/ROP enhancer may be added to the mud pit to resultin a final concentration of lubricant/ROP enhancer in the water baseddrilling mud of between about 1-15% by volume, preferably between about1-2% by volume.

Generally, a spotting fluid is pumped downhole in greater quantitiesthan a lubricant, and is used to dislodge a previously lodged bit. Apreferred spotting fluid is BLACK MAGIC CLEAN, available from BakerHughes INTEQ, which contains 50-80% by volume of C16/C18 IsomerizedOlefins, obtained from Chevron Chemical Co., and 20-50% by volume BLACKMAGIC SACKED FISHING TOOL (SFT), available from Baker Hughes INTEQ.BLACK MAGIC SFT comprises a dry mixture of optimum-size air-blownasphalt, lime, fatty acids, and dispersants available in powdered form.

A second preferred embodiment, which contains no asphalt, is DFE-1310,available from Baker Hughes INTEQ. DFE-1310 has the followingcomposition:

    ______________________________________                                        MATERIAL    CC           G      BBL                                           ______________________________________                                        ISO-TEQ     287.0        226.7  0.82                                          CARBO-GEL                6                                                    Lime                     10                                                   TEQMUL      8.8          8.0                                                  DFE-416     23.6         38.7   0.10                                          NaCl Brine  33.6         38.7   0.10                                          (20%)                                                                         REV DUST                 10                                                   DFE-417                  5                                                    ______________________________________                                    

From the foregoing formula, the following materials are available fromBaker Hughes INTEQ: ISO-TEQ (isomerized olefins); CARBO-GEL (anorganophilic clay); TEQMUL (a Polyamide Emulsifier); DFE-416 (a fattyacid emulsifier); and, DFE-417 (a viscosifier). REV-DUST is a simulateddrilled solid, available from Mil-White, Inc., Houston, Tex.;

DFE-1310 has the following properties:

    ______________________________________                                        PROPERTY              INITIAL                                                 ______________________________________                                        Temperature (°F./°C.)                                                                 120/48.9                                                600 rpm               50                                                      300 rpm               33                                                      200 rpm               26                                                      100 rpm               18                                                       6 rpm                8                                                        3 rpm                7                                                       Plastic Viscosity (cPs)                                                                             17                                                      Yield Point           7.81 g/m.sup.2                                                                (16 lb/100 ft.sup.2)                                    Gels                  3760 g/m.sup.2                                                                (10/13 lb/ft.sup.2)                                     Weight                91.1 g/m.sup.2                                                                (7.6 ppg)                                               Synthetic Water Ratio 90/10                                                   ______________________________________                                    

In a preferred embodiment, the olefin isomer blend for use as a spottingfluid has a concentration of between about 50-95% by volume olefinisomer and between about 5-50% by volume functional additives. Morespecifically, a preferred embodiment contains between about 50-95% byvolume olefin isomer; between about 2-6% by volume emulsifier; betweenabout 0.2-5% by volume viscosifier; between about 2-5% by volumesurfactant; and, between about 1-40% by volume brine. As a spottingfluid, the additive blend may be introduced into the mud pit, to resultin a total concentration in the drilling mud of between about 1-15% byvolume, more preferably between about 3-15% by volume, most preferablybetween about 3-5% by volume. The use of the drilling mud need not beinterrupted when the olefin isomer is added.

The invention will be better understood with reference to the followingexamples:

EXAMPLE 1

A major oil and gas producer working in the High Island Area OffshoreTexas became concerned about low rate of penetration when drilling in a14.92 cm (57/8 inch) hole. The concern was magnified because a 304.8 m(1,000 ft) coring operation was scheduled.

A protective liner was set at 4156.86 m (13,638 ft) in the 28° wellbore.The mud system was a low pH DRILL THIN system, sold by Baker HughesINTEQ, designed to prevent shale dispersion. The drilling fluidcontained 9.33 kg/bbl (25 lb/bbl) of MIL-CARB, a sized calcium carbonateobtained from Baker Hughes INTEQ, to provide low spurt loss. The planwas to core +/-182.88 m (600 ft) of shale, and +/-121.92 m (400 ft) ofsand in a 1.99 g/cm³ (16.6 ppg) pore pressure environment.

After drilling out and testing the shoe, a PDC bit was picked up. Thebit was dressed with 3-14/32 jets while pumping 946.35 liters/min (250gal/min) giving a hydraulic horsepower of 6.35/cm² and 2.5/in². Drillingrates averaged 1.52-2.44 m/hr (5-8 ft/hr). DFE 619 was added to thesuction pit to result in a 2% concentration. The rate of penetrationincreased immediately to 3.05-7.62 m/hr (10-25 ft/hr). The hole wasdrilled down to the core point.

Over the next two days and two coring runs, the rate of penetration wasincreased to 3.35 m/hr (11 ft/hr). One problem was that the DFE 619 hada tendency to "float" on top of the 1.99 g/cm³ (16.6 ppg) mud. Thesweeps allowed the DFE 619 to mix better than when added to the suctionpit. Efforts were made to inject the DFE 619 directly into the lowpressure side of the mud pump, but this caused problems with pressurelosses, either from the diaphragm pump being used or from the densitydifference between the weight of the mud and the DFE 619.

In summary, the rate of penetration was doubled on a consistent basiswhile using DFE 619. The DFE 619 is emulsified quickly in a 1.95 g/cm³(16.3 ppg) drilling fluid. This fluid contained 9.35 g/cm³ (78 lb/bbl)of Ligco and 50.07 kg/bbl (6 lb/bbl) of DRILL THIN.

EXAMPLE 2

The NEW DRILL system was used to drill this section. Casing was testedto 1.77 g/cm³ (14.8 ppg) equivalent mud weight (EMW) and mud weight wasraised from 1.25 g/cm³ (10.4 ppg) to 22.4 g/cm³ (11.2 ppg) whiledrilling cement. While reaming the old hole section below the 2.22 cm(5/8 in) casing, the pipe became stuck at 3097.38 m (10162 ft). BLACKMAGIC CLEAN (40 bbls) was spotted into the drilling mud, and the pipecame free. The bottom hole assembly was changed and reaming was resumedto the bottom of the hole at 3147.67 m (10,327 ft). A short trip wasmade with no problems.

The foregoing demonstrates that BLACK MAGIC CLEAN is an effectivespotting additive for water-based drilling muds.

EXAMPLE 3

A major independent oil and gas producer working in the Matagorda IslandArea Offshore Texas became differentially stuck while conditioning thewell bore following a period of remedial work to cure loss ofcirculation. BLACK MAGIC SACKED FISHING TOOL, obtained from Baker HughesINTEQ, was mixed on location with Baker Hughes INTEQ's Synthetic BasedFluid, ISO-TEQ®, and spotted freeing the stuck pipe in 36 hours.

Prior to the pipe becoming stuck, a very permeable (2 darcy) sand wasbeing drilled. Testing indicated that, with the proper product mix andcorrect concentration, this depleted sand (0.827 g/cm³, 6.9 ppgdifferential) could be successfully drilled without differentialsticking. The sand was drilled down to the lower bedding plane wherethere was a complete loss of returns along the sand/shale interface. Astrong possibility exists that a fracture was caused along this planedue to shrinkage.

After pumping two conventional lost circulation material pills (LCMpills), obtained from Baker Hughes INTEQ, a series of gunk squeezes(prepared with ISOTEQ) were pumped before the wellbore would stay fulland the mud density could be decreased to 1.86 g/cm³ (15.5 ppg) from2.12 g/cm³ (17.7 ppg). The mud was then conditioned with LCM beforeattempting to wash to bottom. While washing to bottom, the drillstringbecame stuck at 3954.48 meters (12,974 ft).

While working the pipe using torque and jarring down and up on the stuckpipe, ISO-TEQ and SFT were mixed in the slugging pit. The final spottingfluid consisted of 0.60 bbls ISO-TEQ, 47.0 ppb SFT, and 495 ppb MILBAR.The following rheological properties were recorded prior to pumping.

Density: 1.86 g/cm³ (15.5 ppg)

Plastic Viscosity: 45 cps @48.9° C. (120° F.)

Yield Point: 22 lb/100 ft² or 10.74 g/m²

Gels: 7/15-10 sec/10 min

Twenty three barrels of ISO-TEQ/SFT were pumped. Five barrels werespotted outside of the pipe leaving the remainder in the drillstring tomove the spot. While continually jarring on the pipe with the drillingjars, 0.5 barrels of spot was moved every thirty minutes. Once awireline unit arrived, a free-point was determined and pipe was backedoff to pick up the fishing jars.

Back on the bottom, the fishing assembly was screwed into the fish. Thepipe came free after being jarred on four times--three times down, onceup. The fish was back reamed 7.62 m (25 ft) back up into the liner. Anaccumulative period of thirty-six hours passed from the time the pipebecame stuck until ISO-TEQ/SFT was spotted and the pipe freed.

The foregoing demonstrates that the mixture of ISOTEQ/SFT is aneffective spotting additive.

EXAMPLE 4

An operator working offshore Texas in the Matagorda Island area becamedifferentially stuck while running a drilling liner through depletedsands. A spotting fluid was mixed at the rigsite using BLACK MAGICSACKED FISHING TOOL (SFT) and ISO-TEQ, both obtained from Baker HughesINTEQ. The pipe came free 61/2 hours after spotting.

The well was drilled through two very permeable (2 and 5 darcy) sandsections separated by 27.43 m (90 ft) of shale. these depleted sandstotaled approximately 131.06 meters (430 feet) in length. Using 1.86g/cm³ (15.5 ppg) mud weight, the pressure differential across the sandswas 224.98 kg/cm² (3,200 psi). To seal the sands, the mud system usedwas a UNICAL System with 0.3 ppb MIL-TEMP, obtained from Baker HughesINTEQ. Selected Seepage Control Materials (SCM) were used: MIL-CARB,obtained from Baker Hughes INTEQ; CHEK-LOSS, obtained from Baker HughesINTEQ; and GILSONITE, obtained from Baker Hughes INTEQ. This sectiondrilled with no problems using judicious drilling practices andoptimized drilling fluids.

The 19.69 cm (73/4 in) lines were being run into the open hole (21.59cm, 81/2 in) when it became stuck 60.96 m (200 ft) below the last linershoe (which put it through the first sand, shale section and into thetop of the second sand). The filter cake development (provided by highpermeability and differential pressure), combined with the tighttolerance (73/4 in casing inside of 81/2 in hole), meant potentiallyconsiderable contact area.

Because of the potential for stuck pipe while drilling and runningcasing, the slug pit was kept clean throughout this interval. ISO-TEQwas stored in one of the rig's tanks and sufficient BLACK MAGIC SACKEDFISHING TOOL (SFT) was kept on board.

The decision was made to mix and spot 50 barrels of ISO-TEQ SFT. Withthe slugging pit already clean, it was only necessary to flush themixing lines before adding the ISO-TEQ fluid into the pit. Then theBLACK MAGIC SFT was added and allowed to shear until smooth (10minutes). The spot was then weighted to 1.87 g/cm³ (15.6 ppg) usingbarite. The material quantities and mud properties were:

    ______________________________________                                        Material Quantities                                                           Product        Quantity Used                                                                             Per Barrel                                         ______________________________________                                        ISO-TEQ        30 barrels  0.6 bbls                                           Water*         1 barrel    0.02 bbls                                          BLACK MAGIC SFT                                                                              47 sacks    23.45 kg (51.7 lb)                                 MILBAR         222 sacks   201.39 kg (444 lb)                                 Mud Properties                                                                Density:         1.87 g/cm.sup.3 (15.6 ppg)                                   Plastic Viscosity:                                                                             39 cps @ 48.9° C. (120° F.)                    Yield Point:     17 lb/100 ft.sup.2                                                            830.01 g/m.sup.2                                             Gel Strength:    6/13 lb/100 ft.sup.2                                                          22.53 g/m.sup.2                                              ______________________________________                                         *The water was incorporated from what was left in the mixing line after       flushing.                                                                

After mixing, the ISO-TEQ/SFT was spotted putting 15 barrels outside thepipe. The spot soaked 2 hours, then 1 barrel was pumped every hour withthe pipe being worked. After 61/2 hours, the pipe came free and drag outof the hole was normal. On the following wiper trip, the hole wascirculated out and the spot was incorporated into the mud system with noill effects; a subsequent reduction in the high temperature/highpressure fluid loss was noted.

The foregoing demonstrates that the ISO-TEQ/SFT mixture is an effectivespotting agent.

EXAMPLE 5

While drilling in Grand Isle Block #25 State Lease (TX) #12746, stuckpipe occurred. A BLACK MAGIC CLEAN pill was used to free the pipe. Thewell was being drilled through depleted sands at 3869.91 meters (12,690ft) measured depth and had ±80,000# drag on the drill string pick upweight. Lubricants were being added and maintained through the mudsystem, but the pipe became stuck while tripping for a new bit. BLACKMAGIC CLEAN was spotted over the open hole section and the pipe becamefree in approximately 1 hour. The jars were not functioning at thistime, and the angle in this section of the hole had been dripped from19.2° to 7.7°. After tripping out of the hole, a hole opener and stringreamer were run to total depth with slight sticking problems. The BLACKMAGIC pill in the hole was incorporated into the mud system with nonegative effects to fluid rheology or other properties. Drill cuttingsand fluids overboard showed no sign of sheening or slick.

Persons of skill in the art will appreciate that many modifications maybe made to the embodiments described herein without departing from thespirit of the present invention. Accordingly, the embodiments describedherein are illustrative only and are not intended to limit the scope ofthe present invention.

We claim:
 1. A drilling fluid additive for water-based drilling mudscomprising olefin isomers comprising between about 8-30 carbon atoms,said olefin isomers comprising a carbon backbone comprising at least onedouble bond located internally within said carbon backbone.
 2. Theadditive of claim 1 wherein a majority of said olefin isomers areselected from the group consisting of olefin isomers comprising 16- and18- carbon atoms.
 3. The additive of claim 1 wherein said olefin isomerscomprise molecules having the following general structure: ##STR2##wherein R¹ and R⁴ independently are selected from the group consistingof straight chain alkyl groups comprising between about 1-28 carbonatoms, and branched alkyl groups comprising between about 1-28 carbonatoms, said branched alkyl groups further comprising between about 0-2substituents selected from the group consisting of alkyl groupscomprising between about 1-5 carbon atoms; and,R² and R³ independentlyare selected from the group consisting of hydrogen and alkyl groupscomprising between about 1-5 carbon atoms, provided that the totalnumber of carbon atoms in said olefin isomers is between about 8-30. 4.The additive of claim 3 wherein said olefin isomers comprise a mixtureof molecules wherein:a majority of said molecules are selected from thegroup consisting of olefin isomers comprising 16- and 18carbon atoms;and, said molecules further comprise between about 0-2 substituentsselected from the group consisting of alkyl groups comprising betweenabout 1-2 carbon atoms.
 5. The drilling fluid additive of claim 1wherein:said additive comprises a spotting fluid; said spotting fluidcomprises between about 50-95% by volume of said olefin isomers; and,said spotting fluid comprises between about 2-6% by volume emulsifier,between about 0.2-5% by volume viscosifier, between about 2-5% by volumesurfactant, and between about 1-40% by volume brine.
 6. The drillingfluid additive of claim 2 wherein: said additive comprises a spottingfluid:said spotting fluid comprises between about 50-95% by volume ofsaid olefin isomers; and, said spotting fluid further comprises betweenabout 2-6% by volume emulsifier, between about 0.2-5% by volumeviscosifier, between about 2-5% by volume surfactant, and between about1-40% by volume brine.
 7. The drilling fluid additive of claim 3wherein: said additive comprises a spotting fluid:said spotting fluidcomprises between about 50-95% by volume of said additive; and, saidspotting fluid further comprises between about 2-6% by volumeemulsifier, between about 0.2-5% by volume viscosifier, between about2-5% by volume surfactant, and between about 1-40% by volume brine. 8.The drilling fluid additive of claim 4 wherein: said additive comprisesa spotting fluid;said spotting fluid comprises between about 50-95% byvolume of said olefin isomers; and, said spotting fluid furthercomprises between about 2-6% by volume emulsifier, between about 0.2-5%by volume viscosifier, between about 2-5% by volume surfactant, andbetween about 1-40% by volume brine.
 9. The drilling fluid additive ofclaim 1 wherein:said additive is selected from the group consisting of alubricant and a rate of penetration enhancer; said additive comprisesbetween about 90-100% by volume of said olefin isomers; and, saidadditive further comprises between about 0-10% by volume surfactant. 10.The drilling fluid additive of claim 2 wherein:said additive is selectedfrom the group consisting of a lubricant and a rate of penetrationenhancer: said additive comprises between about 90-100% by volume ofsaid olefin isomers; and, said additive further comprises between about0-10% by volume surfactant.
 11. The drilling fluid additive of claim 3wherein:said additive is selected from the group consisting of alubricant and a rate of penetration enhancer; said additive comprisesbetween about 90-100% by volume of said olefin isomers; and, saidadditive further comprises between about 0-10% by volume surfactant. 12.The drilling fluid additive of claim 4 wherein:said additive is selectedfrom the group consisting of a lubricant and a rate of penetrationenhancer; said additive comprises between about 90-100% by volume ofsaid olefin isomers; and, said additive further comprises between about0-10% by volume surfactant.
 13. A water-based drilling mud comprisingbetween about 2-15% by volume of a drilling fluid additive comprisingbetween about 8-30 carbon atoms, said olefin isomers comprising a carbonbackbone comprising at least one double bond located internally withinsaid carbon backbone.
 14. The drilling mud of claim 13 a majority ofsaid olefin isomers are selected from the group consisting of olefinisomers comprising 16- and 18- carbon atoms.
 15. The drilling mud ofclaim 13 wherein said olefin isomers comprise molecules having thefollowing general structure: ##STR3## wherein R¹ and R⁴ independentlyare selected from the group consisting of straight chain alkyl groupscomprising between about 1-28 carbon atoms, and branched alkyl groupscomprising between about 1-28 carbon atoms, said branched alkyl groupsfurther comprising between about 0-2 substituents selected from thegroup consisting of alkyl groups comprising between about 1-5 carbonatoms; and,R² and R³ independently are selected from the groupconsisting of hydrogen and alkyl groups comprising between about 1-5carbon atoms, provided that the total number of carbon atoms in saidolefin isomers is between about 8-30.
 16. The drilling mud of claim 13wherein said olefin isomers comprise a mixture of molecules wherein:amajority of said molecules are selected from the group consisting ofolefin isomers comprising 16- and 18carbon atoms; and, said moleculesfurther comprise between about 0-2 substituents selected from the groupconsisting of alkyl groups comprising between about 1-2 carbon atoms.17. The drilling mud of claim 13 wherein:said drilling fluid additivecomprises a spotting fluid; said spotting fluid comprises between about50-95% by volume of said olefin isomers; and, said spotting fluidcomprises between about 2-6% by volume emulsifier, between about 0.2-5%by volume viscosifier, between about 2-5% by volume surfactant, andbetween about 1-40% by volume brine.
 18. The drilling mud of claim 13wherein:said drilling fluid additive is selected from the groupconsisting of a lubricant and a rate of penetration enhancer; saidadditive comprises between about 90-100% by volume of said olefinisomers; and, said additive further comprises between about 0-10% byvolume surfactant.
 19. The drilling mud of claim 14 wherein: saiddrilling fluid additive comprises a spotting fluid:said spotting fluidcomprises between about 50-95% by volume of said olefin isomers; and,said spotting fluid further comprises between about 2-6% by volumeemulsifier, between about 0.2-5% by volume viscosifier, between about2-5% by volume surfactant, and between about 1-40% by volume brine. 20.The drilling mud of claim 14 wherein:said additive is selected from thegroup consisting of a lubricant and a rate of penetration enhancer: saidadditive comprises between about 90-100% by volume of said olefinisomers; and, said additive further comprises between about 0-10% byvolume surfactant.
 21. The drilling mud of claim 15 wherein:saiddrilling fluid additive comprises a spotting fluid: said spotting fluidcomprises between about 50-95% by volume of said additive; and, saidspotting fluid further comprises between about 2-6% by volumeemulsifier, between about 0.2-5% by volume viscosifier, between about2-5% by volume surfactant, and between about 1-40% by volume brine. 22.The drilling mud of claim 15 wherein:said additive is selected from thegroup consisting of a lubricant and a rate of penetration enhancer; saidadditive comprises between about 90-100% by volume of said olefinisomers; and, said additive further comprises between about 0-10% byvolume surfactant.
 23. A process comprising the step of adding to awater-based drilling mud between about 1-15% by volume of a drillingfluid additive comprising olefin isomers comprising between about 8-30carbon atoms, said olefin isomers comprising a carbon backbonecomprising at least one double bond located internally within saidcarbon backbone.
 24. The process of claim 23 wherein a majority of saidolefin isomers are selected from the group consisting of olefin isomerscomprising 16- and 18- carbon atoms.
 25. The process of claim 23 whereinsaid olefin isomers comprise molecules having the following generalstructure: ##STR4## wherein R¹ and R⁴ independently are selected fromthe group consisting of straight chain alkyl groups comprising betweenabout 1-28 carbon atoms, and branched alkyl groups comprising betweenabout 1-28 carbon atoms, said branched alkyl groups further comprisingbetween about 0-2 substituents selected from the group consisting ofalkyl groups comprising between about 1-5 carbon atoms; and,R² and R³independently are selected from the group consisting of hydrogen andalkyl groups comprising between about 1-5 carbon atoms, provided thatthe total number of carbon atoms in said olefin isomers is between about8-30.
 26. The process of claim 23 wherein said olefin isomers comprise amixture of molecules wherein:a majority of said molecules are selectedfrom the group consisting of olefin isomers comprising 16- and 18-carbonatoms; and, said molecules further comprise between about 0-2substituents selected from the group consisting of alkyl groupscomprising between about 1-2 carbon atoms.